Weblabor

class Point {
    constructor(x, y) {
        this.x = x;
        this.y = y;
    }
    toString() {
        return '(' + this.x + ', ' + this.y + ')';
    }
}

class ColorPoint extends Point {
    constructor(x, y, color) {
        super(x, y);
        this.color = color;
    }
    toString() {
        return super.toString() + ' in ' + this.color;
    }
}

function Point(x, y) {
    this.x = x;
    this.y = y;   
}

Point.prototype.toString = function() {
    return '(' + this.x + ', ' + this.y + ')';
};

function ColorPoint(x, y, color) {
    ColorPoint.super_.call(this, x, y);
    this.color = color;    
}
util.inherits(ColorPoint, Point);

ColorPoint.prototype.toString = function() {
    return ColorPoint.super_.prototype.toString.call(this) + ' in ' + this.color;
};